1. Field of the Invention
The present invention relates to a bonding tool, an electronic component mounting apparatus and an electronic component mounting method for mounting an electronic component on a circuit board or the like.
2. Related art of the Invention
There are many known bonding methods for bonding a bump electrode of an electronic component to an electrode on a printed circuit board.
For example, an ultrasonic bonding method, which is one of such bonding methods, is capable of bonding an electronic component to a circuit board in a short time.
Here, the ultrasonic bonding method is a bonding method that, while pressing an electronic component held on a bonding action part against the circuit board, makes the electronic component vibrate by ultrasonic vibration so as to bond electrically an electrode of the electronic component to an electrode of a circuit board at the atomic level by utilizing bonding caused by destruction and dispersion of the surface coating induced from local slip at the contact surface.
Referring to FIG. 16, a configuration and an operation of a conventional bonding tool using the above-mentioned ultrasonic bonding method will be described.
FIG. 16 is a schematic partial cross-sectional view of a conventional bonding tool 1000.
The conventional bonding tool 1000 is an apparatus for making an electronic component 1910 vibrate by an ultrasonic transducer 1400 so as to bond the electronic component 1910 to a circuit board 1920 (see Japanese Patent Laid-Open No. 2005-347505, for example).
The entire disclosure of the literature described above is incorporated herein by reference in its entirety.
A horn 1200 is shaped like a prism with a longitudinal direction agreeing with the X direction, and an ultrasonic vibration, which is generated by the ultrasonic transducer 1400 provided at one end of the horn 1200 on the (−X) side, is transmitted through the horn 1200 in the X direction and applied to the electronic component 1910 via a bonding action part 1500.
The reliability of bonding of the electronic component 1910 to the circuit board 1920 is improved using a heater 1600 inserted from the (+X) side into a heater installation cavity part 1610 which penetrates the horn 1200 in the X direction in which the ultrasonic vibration is transmitted.
That is, heat produced by the heater 1600 is transmitted through the horn 1200 and then applied to the electronic component 1910 via the bonding action part 1500.
Lead lines 1810 and 1820 are lines for connecting the heater 1600 and a thermocouple 1700 to an external power supply (not shown), respectively, and are coupled to a bracket 1110 fastened to a lift block 1100.
The heat produced by the heater 1600 is also transmitted to the ultrasonic transducer 1400 via the horn 1200.
In a consequence, concerning the heat-sensitive ultrasonic transducer 1400, there is some fear of a shortening of its life span, a change of its electrical characteristics, a variation of its vibration characteristics and so on.
Accordingly, a cooling part 1300 of four air holes is provided between the heater 1600 and the ultrasonic transducer 1400, the four air holes penetrating the horn 1200 in the Y direction perpendicular to the X direction in which the ultrasonic vibration is transmitted with air being supplied via a suction pad 1310 to flow through the four air holes.
Thus, the heat which would otherwise be transmitted to the ultrasonic transducer 1400 is diffused by the air flowing through the air holes, and the adverse effect of the heat produced by the heater 1600 on the ultrasonic transducer 1400 is reduced.